1				2				3							4							5
		6
																7				8
																		9
				10
				11							12
	13
				14									15									16
	17
													18
			19																20
21
															22
	23
											24
	25
26														27
					28

Across 4. A large grouping of stars. Galaxies are found in a variety of sizes and shapes. Our own Milky Way galaxy is spiral in shape and contains several billion stars. Some galaxies are so distant the their light takes millions of years to reach the Earth. 6. A constellation in the shape of a cross 10. The apparent dimming of star or planet when low on the horizon due to absorption by the Earth's atmosphere. 11. A Dwarf Planet in the Milky way 12. A term used to describe matter in the universe that cannot be seen, but can be detected by its gravitational effects on other bodies. 13. The law of physics that states that the farther a galaxy is from us, the faster it is moving away from us. 15. A small planetary body in orbit around the Sun, larger than a meteoroid but smaller than a planet. Most asteroids can be found in a belt between the orbits of Mars and Jupiter. The orbits of some asteroids take them close to the Sun, which also takes them across the paths of the planets. 17. A bowl-shaped depression formed by the impact of an asteroid or meteoroid. Also the depression around the opening of a volcano. 19. A group of stars making a figure 21. When an object is blocking your vision from something 22. A hollow, irregular depression. 23. Something that orbits around a planet 24. A strong substance on Earth that pulls us down to the Earth 25. An extremely bright meteor. Also known as bolides, fireballs can be several times brighter than the full Moon. Some can even be accompanied by a sonic boom. 26. Flying object in space 27. The two points at which the Sun crosses the celestial equator in its yearly path in the sky. The equinoxes occur on or near March 21 and September 22. The equinoxes signal the start of the Spring and Autumn seasons. 28. They are everywhere in the night sky.

Down 1. It orbits the Earth 2. A really hot ball of gas in the MilkyWay 3. An increase in temperature caused when incoming solar radiation is passed but outgoing thermal radiation is blocked by the atmosphere. Carbon dioxide and water vapor are two of the major gases responsible for this effect. 5. There are 8 of them in the MilkyWay 6. Endless space of stuff. 7. The theory that suggests that the universe was formed from a single point in space during a cataclysmic explosion about 13.7 billion years ago. This is the current accepted theory for the origin of the universe and is supported by measurements of background radiation and the observed expansion of space. 8. A glow in a planet's ionosphere caused by the interaction between the planet's magnetic field and charged particles from the Sun. This phenomenon is known as the Aurora Borealis in the Earth's northern hemisphere and the Aurora Australis in the Earth's Southern Hemisphere. 9. A cloud surrounding Earth full of comets 12. A celestial body orbiting the Sun that is massive enough to be rounded by its own gravity but has not cleared its neighboring region of planetesimals and is not a satellite. It has to have sufficient mass to overcome rigid body forces and achieve hydrostatic equilibrium. Pluto is considered to be a dwarf planet. 14. A layer of gases surrounding a planet, moon, or star. The Earth's atmosphere is 120 miles thick and is composed mainly of nitrogen, oxygen, carbon dioxide, and a few other trace gases. 16. Sucks things up into another dimension 18. The Galaxy in which the Earth lives 20. The amount of matter contained within a given volume. Density is measured in grams per cubic centimeter (or kilograms per liter). The density of water is 1.0, iron is 7.9, and lead is 11.3.